Wireless communication networks such as Fourth Generation (4G, also referred to as Long Term Evolution (LTE)) networks are presently widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. However, whilst current 4G technology offers much faster data rates than its previous generations, it has limitations due to its bandwidth, scalability and number of users under individual cells.
The new radio (NR) standard for 5G networks has been developed and is being rolled out to provide new functionalities including enabling the connection of many things in, for example, the Internet of Things (IoT) with low latency and very greatly increased speeds. NR builds upon today's LTE networks, expanding and improving existing coverage with the goal to facilitate enhanced mobile broadband by using 5G small cells to boost the data rates on an LTE anchor network. Consequently, the 5G Radio Access architecture is composed of LTE Evolution and an NR Access Technology operable from about 1 GHz to about 100 GHz.
The telecommunications system is therefore moving towards a flatter architecture where macro and metro cells are directly, or indirectly, connected through one or more gateway (GW) nodes or devices to the core network. The GW nodes act as signal and data path aggregators. An increase of user subscription also contributes to the increase in the amount of network signaling. Analysis has shown that a network core entity, such as the Evolved Packet Core (EPC) Mobility Management Entity (MME) may experience a sustained signaling load of over 500-800 messages per user equipment (UE) during normal peak busy hours and up to 1500 message per UE per hour under heavy usage conditions. In modern systems, it is therefore common to densely deploy many small cells to improve coverage which inherently involves much more frequent handovers taking place between base stations.
The S1 Application Protocol (S1AP) is a signaling protocol between the base stations, e.g. Evolved NodeB (eNodeB), and the core network, e.g. the EPC. The S1AP protocol carries control signaling between an eNodeB and the MME on an S1-MME interface. The S1AP protocol carries upper layer Non Access Stratum (NAS) messages for the EPC and the UEs and manages data paths between base stations and the core network. When a large number of base stations need to connect to the core network, a GW node may be used as an aggregator of the connections from these base stations such that a high amount of signaling messages are required to be handled by the GW node.
A number of technical problems arise in the presence of the GW node(s), including that a user data path creation process between a UE and a core network node cannot directly or explicitly identify a previously created user data path between said UE and a core network node. The S1AP protocol does not link or does not provide information linking these two processes, because the use data path creation process and the user data path removal process may be implemented in different GW nodes and, even if both are implemented by a same GW node, the processes are by their nature independent of each other, namely one removes a previously created user data path and the other independently creates a new user data path. For handover of a UE from one base station to another, there is no technical requirement for the new data path creation process to be linked, i.e. have knowledge of, the data path removal process even when the two processes are implemented in the same GW node for a specified UE. Also, a GW node operating the S1AP protocol has no access to the permanent UE ID, e.g. the unique international mobile subscriber identity (IMSI), which is found in the NAS layer. The absence of a common ID or the like to link a UE connection resource to an existing user data path for said UE prevents a GW node handling handover of the UE from a source base station (SBS) to a target base station (TBS) from reusing the already existing user data path.
WO2014019554 discloses that a bearer path can be optimized following a mobile relay node (MRN) handover in order to directly re-route the bearer path from a UE core network to a target donor base station (De NB). Bearer path optimization signaling includes a packet data network gateway (PGW) relocation information element (IE) indicating that a PGW of an MRN is being relocated from an initial De NB to a target De NB. The PGW relocation IE may be carried in a path switch request message. Bearer path optimization signaling also includes an NAS activate default enhanced packet switch (EPS) bearer context request/accept messages for activating the optimized bearer path. The NAS activate default EPS bearer request/accept messages may be communicated between the mobile relay node MME and the MRN via the target De NB.
US20150208291 discloses a communication method of an MME supporting inter-gateway handover of a terminal includes acquiring, when a handover from a source gateway to a target gateway is detected during an ongoing data communication of the terminal, information on a session between the terminal and a server and transmitting, when the server is a local server present in a mobile communication core network, a tunnel setup command to the local server through an interface established with the local server, the tunnel setup command instructing to establish a tunnel between the local server and the target gateway for data communication from the local server to the target gateway.
US20160044559 discloses a method and apparatus for transmitting a Handover Request message in a wireless communication system. For service differentiation from a small cell and a macro cell, a first macro eNB transmits a Handover Request message including a list of first services for a UE, which are provided by the first macro eNB, and a list of second services for the UE, which are provided by a small cell eNB which has dual connectivity with the first macro eNB.
None of WO201401955, US20150208291 and US20160044559 makes use of the fact that, where a same GW node handles the existing user data path removal process and the new user data path creation process, all of the information that could be used for modifying and re-using an existing user data path passes through said GW node even though such information is not linked together.
In light of the above, there is a need to better manage path resources between a GW node and base stations in a mobile wireless communication network to reduce overhead and improve efficiency of mobile communications.